In the past, fuel injectors were relatively simple mechanical devices that utilized conventional sealing strategies, such as o-rings, to prevent fuel leakage from the injector. As the sophistication of engines has developed, fuel injectors have become electronically controlled via one or more electrical actuators that are often positioned within the fuel injector body. For instance, in one class of fuel injector, a cam driven plunger is utilized to pressurize fuel to injection pressure levels, typically once per engine cycle. The timing of that pressurization event may be controlled by an electronically controlled spill valve, and the timing of the injection event may be controlled via an electronic needle control valve. While it is known to use piezo's as electrical actuators in fuel injectors, most fuel injectors continue to utilize high speed solenoids as electrical actuators. For instance, in the example injector identified previously, separate solenoids would be utilized to close the spill valve to raise fuel pressure to injection levels, and a second electrical actuator would be utilized to move a valve to relieve pressure in a control chamber acting on a closing hydraulic surface of a nozzle check valve member.
The utilization of electrical actuators in fuel injectors has raised new sealing problems in how to bring electrical power to the electrical actuators without creating new avenues for fuel leakage from the fuel injector. Adequately sealing against fuel leakage will prevent fuel to oil dilution that could undermine the lubricity of the engine oil. One such example sealing element for a piezo actuator of a fuel injector is shown, for instance, in U.S. Pat. No. 7,097,484. This device uses an elastomeric member with external ridges to provide sealing with regard to an injector body, and internal passages that receive and grip electrical conductors to prevent fuel migration along the surface of the electrical conductors. Thus, while there are a variety of sealing strategies known in the fuel injector art, other problems associated with sealing exist, such as those associated with assembling the fuel injector without undermining the sealing strategy. For instance, misassembly opportunities that allow for a sealing member to become torn, scratched, or otherwise damaged during the assembly procedure can otherwise undermine an apparently sound sealing strategy.
The present disclosure is directed to one or more of the problems set forth above.